A total of 23 people have been arrested and dozens of weapons seized in a series of raids on suspected Islamist militants across France, officials say.

The crackdown follows multiple attacks on bars, restaurants, a concert hall and a stadium in Paris on Friday, in which 129 people were killed.

Belgian police say two people arrested on Saturday have been charged with "participating in a terrorist attack".

They were among seven people detained in Belgium at the weekend.

Five of them were later released, including Mohammed Abdeslam, the brother of two suspects - Brahim Abdeslam, killed during the attacks, and Salah Abdeslam, who is on the run.

French PM Manuel Valls said the attacks had been organised from Syria. He added that the authorities believed new terror attacks were being planned in France and other European countries.

Two more Paris attackers have been named as Ahmad al-Mohammad and Samy Amimour, along with five already identified.

As well as the attackers themselves, investigators are also reported to be focusing on a Belgian of Moroccan descent who is described as the possible mastermind of the attacks. Abdelhamid Abaoud, 27, lived in the Molenbeek neighbourhood of Brussels, as did two of the attackers, and is now believed to be based in Syria, where he has risen through the ranks of IS.

Police have named Brussels-born Salah Abdeslam, 26, as a key suspect, and a manhunt is under way. He was reportedly stopped by officers in the wake of the attacks while crossing into Belgium but then let go.

People observe a minute of silence in tribute to the victims of the attacks in Paris yesterday in Lille, northem France. Photo: AFP

Belgian police carried out a raid in the Molenbeek neighbourhood, which is considered to be a heaven for jihadists, yesterday morning in an attempt to capture Salah Abdeslam, but no arrests were made.

French Police sources told news agencies that properties in the Paris suburb of Bobigny, as well as the cities of Grenoble, Toulouse and Lyon, had been targeted.

Interior Minister Bernard Cazeneuve said 23 people had been arrested and dozens of weapons seized, including a Kalashnikov assault rifle and rocket launchers. More than 100 have been placed under house arrest.

Seven attackers died in the assault on the French capital, most of them after detonating suicide belts.

France is currently marking a second day of national mourning. A state of emergency declared by President Hollande remains in force. Thousands of extra police and troops are on the streets of Paris.